On a CM-at-risk or negotiated GC project, the GMP proposal is the defining preconstruction deliverable. It's the moment when open-book estimating and collaborative design give way to a committed number — a price the contractor guarantees not to exceed, with specific exclusions, contingencies, and assumptions that define exactly what that guarantee covers.
A poorly built GMP proposal creates disputes. Owners discover that the "guaranteed" price excluded 15% of the scope. GCs discover their contingencies weren't sufficient and absorb cost overruns. A well-built GMP proposal creates clarity — both parties understand what's priced, what's excluded, and what happens when conditions change.
This article walks through the components of a complete GMP proposal package and how to assemble each one. For foundational context on how GMP contracts work, see GMP contract.
When a GMP Proposal Is Required
GMP proposals arise on negotiated delivery methods — CM-at-risk (CMAR) and sometimes design-build — where the contractor is engaged during design rather than selected through competitive lump-sum bidding. The typical timeline:
1. Owner engages CM or GC during schematic design or design development
2. Contractor provides preconstruction services: estimating, constructability review, schedule development, subcontractor market analysis
3. At a defined design completion milestone (typically 60–90% construction documents), the contractor submits a GMP proposal
4. Owner and contractor negotiate and execute a GMP amendment to the existing construction management agreement
5. Construction proceeds under the committed GMP
The earlier in design the GMP is set, the more contingency is required to cover design risk. Setting a GMP at 60% CDs requires more owner contingency than setting it at 95% CDs. Understand where you are in design before committing to a number (Procore, "GMP Contracts in Construction," 2026).
The Core Components of a GMP Proposal Package
1. Cover Letter and Executive Summary
The cover letter should state: the project name, the basis of the GMP (which design documents were used), the GMP amount, the date, and any critical conditions attached to the proposal. Owners and their advisors often read the cover letter before the cost detail — make sure it accurately represents the scope and key exclusions up front.
The executive summary provides a condensed view of cost categories, contingency breakdown, and key assumptions — useful for owner reviews involving legal counsel, lenders, or board approval where not everyone will review the full package.
2. Cost Summary by Trade
The most detailed and important section of the GMP package is the trade cost breakdown. This should be organized by CSI MasterFormat division (or the project's established cost code structure) and show:
- Subcontractor bid amounts or committed contract values for awarded trades
- Allowances for trades not yet awarded (with methodology noted)
- General conditions costs — superintendent, project manager, site trailer, temporary utilities, safety, dumpsters, etc.
- Self-performed work, if any, priced at internal rates
For each trade, the basis of the number should be identifiable: is this a committed sub price, a leveled bid from multiple sub proposals, an estimate against incomplete drawings, or an allowance for scope to be defined?
This is where bid leveling rigor matters. Before locking a GMP number, every sub trade should go through a structured scope comparison — not just price comparison. A concrete sub who is $40,000 lower than competitors because they excluded haul-off and disposal isn't a cheaper option; they're a hidden cost. Melt Bid (https://www.meltplan.com/bid) automates this process by reading subcontractor proposals, flagging scope gaps and exclusions, and producing a normalized comparison that shows the true cost of each bid. Firms that level bids before setting GMP numbers build contingencies based on reality, not assumptions.
3. Contractor's Fee
The GMP includes the contractor's fee — the profit and overhead markup above the cost of the work. Fee is typically expressed as a percentage of total cost of work, agreed in the original CM agreement, and applied in the GMP to yield the total GMP amount.
The GMP proposal should show the fee explicitly: cost of work subtotal, plus fee percentage, plus contingency, equals GMP total. Owners should be able to verify this math independently.
4. Contingencies
Most GMP proposals include two distinct contingency categories:
**Contractor contingency.** Owned by the contractor and used at their discretion to cover cost growth within the defined scope — subcontractor failure, productivity shortfalls, material waste, minor scope growth within the design intent. A typical contractor contingency is 2–5% of cost of work, depending on design completeness and project risk profile.
**Owner contingency (or design contingency).** Held by the owner, or in some contracts held in the GMP but subject to owner approval to release. This covers scope changes directed by the owner, design changes that expand scope, or allowance shortfalls when undefined scope is later priced. Owner contingency is separate from contractor contingency and is not available to the contractor without a change order.
The GMP proposal should define each contingency clearly, state who controls each, and describe the mechanism for releasing funds from contingency to address actual cost events (Autodesk, "GMP Contracts in Construction," 2026).
5. Allowances
Allowances are budget placeholders for defined scope items that cannot yet be precisely priced — because material selections are incomplete, vendor quotes are not yet available, or quantities are not yet determined.
Common GMP allowances:
- Landscaping and site work finishes (pending owner selection)
- Owner-selected fixtures, finishes, or equipment above base specification
- Testing and inspection services
- Utility connection fees (pending utility company confirmation)
- Permit fees above a threshold amount
Each allowance should state: what it covers, the dollar amount, and what triggers reconciliation. If the actual cost of the allowance scope exceeds the allowance, the difference is a change order. If it comes in below, the savings typically flow back to the owner or reduce contractor contingency.
6. Assumptions and Exclusions
This is the most legally significant section of the GMP package. The assumptions and exclusions list defines the boundary of the guarantee.
**Assumptions** describe the design conditions the GMP is predicated on — for example:
- "GMP assumes the structural system will remain as shown on the SD drawings dated . Material structural changes will require a GMP amendment."
- "GMP assumes site soil conditions as described in the geotechnical report dated . Differing site conditions will be treated as a change order."
**Exclusions** are items not priced in the GMP:
- Owner-furnished/contractor-installed equipment
- Furniture, fixtures, and equipment beyond base spec
- Telecom, AV, and security system design and procurement
- Third-party inspections and testing above code minimum
- Owner's consultant fees (architect, engineer, testing lab)
Exclusions buried in fine print create disputes. A well-structured GMP package presents exclusions clearly and prominently, not at the end of an appendix (Quarry View Building Group, "GMP Development for Budget Control," 2026).
7. Basis of Design
The GMP proposal must reference the specific design documents it is based on. Include:
- Architectural drawing set name, date, and revision number
- Structural, MEP, civil, and specialty drawing set dates
- Specifications document version and date
- Any RFIs or clarifications issued and incorporated
If the design evolves after the GMP is set, changes to the scope of work are documented via change orders against the basis of design. Without a clear basis of design reference, determining what is and is not a change order becomes a matter of negotiation rather than fact (Southron Firm, "GMP Contracts Explained," 2026).
8. Project Schedule
The GMP proposal should include or reference an updated project schedule that establishes:
- Preconstruction completion milestone
- Construction start date
- Major milestone sequence (foundation, structure, enclosure, MEP rough-in, finishes, substantial completion)
- Substantial completion date that aligns with the guaranteed completion commitment
If the schedule changes after GMP execution, delay impacts on general conditions costs should be addressed through the change order process.
Assembling the Package: Process Checklist
Before submitting a GMP proposal, verify:
[ ] All major trade bids leveled and scope-confirmed before committing values
[ ] Contingency percentage validated against design completeness level
[ ] Allowances for undefined scope explicitly listed with dollar amounts
[ ] Assumptions and exclusions reviewed by legal counsel before submission
[ ] Basis of design documents specifically referenced by date and revision
[ ] Schedule reviewed for constructability and aligned with GMP cost of general conditions
[ ] Fee verified against contract and applied correctly to cost subtotal
[ ] Cover letter accurately summarizes all material assumptions and exclusions
What Happens After GMP Execution
Once the owner accepts the GMP proposal and executes the GMP amendment, the contractor proceeds to complete subcontractor buyout for any trades priced on allowances or not yet awarded. For context on the full construction procurement process that follows GMP execution, including buyout and subcontractor management, see our procurement guide.
Savings below the GMP (contractor cost of work plus fee coming in below the guaranteed amount) are typically shared between owner and contractor under a shared savings provision, the split of which was negotiated in the original CM agreement. This incentivizes the contractor to pursue value engineering and efficient buyout without reducing scope.
FAQ
**What is the difference between a GMP and a lump sum contract?**
In a lump sum contract, the contractor absorbs all cost risk — if costs exceed the lump sum, that's the contractor's problem. In a GMP contract, the owner receives a cost ceiling but retains the benefit of savings below that ceiling (minus the contractor's share). GMP contracts are typically used on CM-at-risk delivery where the contractor was engaged during design and did not compete in a sealed-bid environment.
**Who prepares the GMP proposal?**
The GMP proposal is prepared by the general contractor or construction manager engaged on a negotiated basis. It is built from subcontractor bids, self-performed work pricing, and the contractor's own general conditions estimate.
**What is a reasonable contingency percentage for a GMP?**
Contractor contingency typically ranges from 2–5% of cost of work. Projects with incomplete design documents at GMP execution warrant higher contingency. Owner contingency is typically held separate and sized based on owner risk tolerance and design status — a range of 3–8% of construction cost is common for institutional owners.
**Can the GMP be amended?**
Yes. Change orders and GMP amendments are the mechanism for addressing scope changes, allowance variances, differing site conditions, and other events that are outside the risk the contractor assumed in the GMP. Controlling GMP amendments through disciplined change order management is a core responsibility of the project team.
**What happens if the contractor exceeds the GMP?**
The contractor absorbs cost above the GMP — that's the "guarantee." The exception is scope changes formally authorized by the owner through change orders. Poorly defined exclusions and allowances are the most common source of GMP overrun disputes.
Conclusion
A GMP proposal package is more than a price — it's a risk allocation document. The assumptions, exclusions, contingencies, and allowances define what the guarantee actually covers. Owners and contractors who invest in building a detailed, clearly documented GMP package avoid the disputes that arise when a "guaranteed" number turns out to have large holes in it.
The foundation of a credible GMP is rigorous bid leveling before committing sub trade values. Every gap in scope comparison at the GMP stage becomes a change order or a dispute during construction. See construction RFP for guidance on the procurement process that generates the subcontractor bids that go into your GMP.
REFERENCES
1. Procore. "Guide to Guaranteed Maximum Price (GMP) Contracts in Construction." procore.com/library. Accessed May 2026.
2. Autodesk. "Navigating Guaranteed Maximum Price (GMP) Contracts in Construction." autodesk.com/blogs/construction. Accessed May 2026.
3. Southron Firm. "GMP Contracts Explained — Guaranteed Maximum Price Guide." southronfirm.com/blog. Accessed May 2026.
4. Quarry View Building Group. "GMP Development for Smarter Construction Budget Control." quarryviewbuildinggroup.com. Accessed May 2026.
5. Document Crunch. "GMP in Construction: Meaning, Benefits & Contract Types." documentcrunch.com/blog. Accessed May 2026.
6. AACE International. "Cost Estimate Classification System." aacei.org. Accessed May 2026.
7. constructionbids.ai. "GMP Guaranteed Maximum Price Construction Guide." constructionbids.ai/blog. Accessed May 2026.